#include<stdio.h>

int prime(int b) {
	int t = 0, i;

	for (i = 2; i < b; i++)

	{
		if (b % i == 0) { t = 1; break; }
	}

	return t;

}

int main() {
	int a, r;

	scanf("%d", &a);

	r = prime(a);

	if (r == 0) printf("%d is a prime.", a);

	else printf("%d is not a prime.", a);





}